(16) باب الأَمْرِ بِإِجَابَةِ الدَّاعِي إِلَى دَعْوَةٍ
Ibn Umar (Allah be pleased with them) reported Allah's Messenger (may be upon him) having said this:
Accept the feast, when you are invited.
Reference: Sahih Muslim 1429 d
In-book reference: Book 16, Hadith 115
USC-MSA web (English) reference(deprecated numbering scheme): Book 8, Hadith 3340